UGNET-NOV2017-III: 45

Question

A signal processor software is expected to operate for 91.25 days after repair, and the mean software repair time is expected to be 5 minutes. Then, the availability of the software is:

(1) 96.9862%

(2) 97.9862%

(3) 98.9962%

(4) 99.9962%

Answer 1

Total Uptime = 91.25 days(Given)

Total Downtime = 5 mins. =5/60 hrs. = 0.083 hrs. (Given)

Now substitute these values in the expression:

Availability = Total uptime/(total uptime+total downtime)

Availability = {91.25*24/(91.25*24+0.083)*100}.

                 = (2190/ (2190+0.083))*100

                 = (2190/2190.083)*100

                 = 0.9996211481*100

                 = 99.9962%

Answer is option (4)

Answer 2

Total uptime=91.25*24 (In hours)

Total downtime=5/60(In hours)=0.083 hours

Availability = Total uptime/(total uptime+total downtime)
By substituting the values we have,

{91.25*24/(91.25*24+0.083)*100}.
After solving this expression the answer evaluates to option D).

Comments

{91.25*24/(91.25*24+6)*100}.

why to use 6, when downtime is 5 mins.

It gives 99.726% which is not in the option

downtime is 5 mins. so first we have convert it into hrs.

Therefore. 5 mins = 5/60 hrs. = 0.083 hrs.

After that we will put values in the expression

Availability = {91.25*24/(91.25*24+0.083)*100}.

                 = (2190/ (2190+0.083))*100

                 = (2190/2190.083)*100

                 = 0.9996211481*100

                 = 99.9962%

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@Roma_Nagpal,Yes I agree that I substituted the wrong value 6 instead of 5  in the formula. You've converted the given values in hours. So that is how you've arrived at the right answer. Please can you share the right answer now. It'll be of help to others as well. :)